BaseAudioContext.createAnalyser()

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createAnalyser() 方法在 BaseAudioContext interface creates an AnalyserNode , which can be used to expose audio time and frequency data and create data visualisations.

注意 : For more on using this node, see the AnalyserNode 页面。

句法

var analyserNode = baseAudioContext.createAnalyser();

AnalyserNode .

范例

The following example shows basic usage of an AudioContext to create an Analyser node, then use requestAnimationFrame() to collect time domain data repeatedly and draw an "oscilloscope style" output of the current audio input. For more complete applied examples/information, check out our Voice-change-O-matic demo (see app.js lines 128–205 for relevant code).

var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var analyser = audioCtx.createAnalyser();
  ...
analyser.fftSize = 2048;
var bufferLength = analyser.frequencyBinCount;
var dataArray = new Uint8Array(bufferLength);
analyser.getByteTimeDomainData(dataArray);
// draw an oscilloscope of the current audio source
function draw() {
      drawVisual = requestAnimationFrame(draw);
      analyser.getByteTimeDomainData(dataArray);
      canvasCtx.fillStyle = 'rgb(200, 200, 200)';
      canvasCtx.fillRect(0, 0, WIDTH, HEIGHT);
      canvasCtx.lineWidth = 2;
      canvasCtx.strokeStyle = 'rgb(0, 0, 0)';
      canvasCtx.beginPath();
      var sliceWidth = WIDTH * 1.0 / bufferLength;
      var x = 0;
      for(var i = 0; i < bufferLength; i++) {
        var v = dataArray[i] / 128.0;
        var y = v * HEIGHT/2;
        if(i === 0) {
          canvasCtx.moveTo(x, y);
        } else {
          canvasCtx.lineTo(x, y);
        }
        x += sliceWidth;
      }
      canvasCtx.lineTo(canvas.width, canvas.height/2);
      canvasCtx.stroke();
    };
    draw();

规范

规范	状态	注释
Web 音频 API The definition of 'createAnalyser()' in that specification.	工作草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`createAnalyser`	Chrome 10 Prefixed 10 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge ≤18	Firefox 53 注意事项 53 注意事项 Originally implemented on `AudioContext` in Firefox 25.	IE 不支持 No	Opera 22 22 15 Prefixed Prefixed Implemented with the vendor prefix: webkit	Safari 6 Prefixed 6 Prefixed Prefixed Implemented with the vendor prefix: webkit	WebView Android Yes	Chrome Android 33	Firefox Android 53 注意事项 53 注意事项 Originally implemented on `AudioContext` in Firefox Android 26.	Opera Android 22 22 14 Prefixed Prefixed Implemented with the vendor prefix: webkit	Safari iOS 6 Prefixed 6 Prefixed Prefixed Implemented with the vendor prefix: webkit	Samsung Internet Android 2.0

图例

完整支持
不支持

要求使用供应商前缀或不同名称。

另请参阅

使用 Web 音频 API

元数据

最后修改： Mar 18, 2019

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